Integrated circuits are available in many different packages, technologies, and sizes. Most integrated circuits are available in plastic packages, which are generally intended for commercial operating environments at a low cost. Commercial operating environments have a specified operating range from 0° C. to 70° C. Integrated circuits for military applications have historically been packaged in either metal or ceramic hermetic packages, which are able to work reliably in more demanding environments than commercial integrated circuits. Military operating environments have a specified operating range from −55° C. to 125° C. In order to save costs, the military has purchased integrated circuits through COTS (Commercial Off-The-Shelf) programs. However, these components are generally commercial grade components in plastic packages, and not intended for demanding environments requiring the broader temperature range reliability and durability of ceramic and metal hermetically packaged integrated circuits.
Depending on size and complexity, integrated circuits are available in a wide range of packages. Although many older integrated circuits were packaged using through-hole technology packages, surface mount packages have dominated over the past several decades. Surface mount packages generally have circuit density, cost, and other advantages over through-hole integrated circuits. Examples of through-hole packages include DIP (dual-in-line plastic) and PGA (pin grid array). Examples of surface mount packages include SOIC (small-outline integrated circuit) and PLCC (plastic leaded chip carrier).
In many cases, products requiring integrated circuits are in production or service for a longer time period than the manufacturing lifetime of a given integrated circuit. In such cases, it is not uncommon for parts to become obsolete or become unable to be purchased. For example, in a typical month, about 3% of all packaged integrated circuit product types become obsolete. One mitigating approach to this issue is to buy a sufficient lifetime inventory of spares for integrated circuits that are likely to become obsolete at a future date. However, this may be costly if a large quantity of integrated circuits needs to be purchased as spares. It also may result in far more spares being purchased that are actually required, since projected future needs may only be a rough estimate. If spares are needed in the future, when an IC is no longer in active production, the ICs that are actually available may be in a different package than is required, since popular ICs are typically offered in multiple package options. For example, spares may be available in plastic DIP packages while qualified assemblies require SOIC packages.